Make airport markers minimal and de-cluttered for global airport density (#5)

* Initial plan

* chore: outline plan for global airport dataset update

Co-authored-by: kewonit <108450560+kewonit@users.noreply.github.com>

* feat: expand airport dataset to 9k+ global airports

Co-authored-by: kewonit <108450560+kewonit@users.noreply.github.com>

* feat: make airport dots subtle and resilient

Co-authored-by: kewonit <108450560+kewonit@users.noreply.github.com>

---------

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>
Co-authored-by: kewonit <108450560+kewonit@users.noreply.github.com>

src/components/ui/control-panel.tsx

@@ -484,7 +484,7 @@ function SearchContent({
 
           {!query && (
             <p className="px-3 pt-3 pb-1 text-center text-[10px] font-medium text-white/10">
-              Search 400+ airports worldwide
+              Search 9,000+ airports worldwide
             </p>
           )}
         </div>